Zatar Lightboard was an interesting project for us. Not only did we design and develop both mobile- and web-applications where multiple users could login in to one device, we designed and developed the device itself (the internet-connected lightboard) from scratch as well.
With use of LED strips and a raspberry pi, we used this project to get acquainted with Light-Weight Machine-to-Machine communication protocol (LWM2M), so that the settings of the lightboard could be adjusted both from the device itself and from the server.
We wanted the actual lightboard itself to give feedback to the user that the color change of a letter was actually performed on the device. So for remote use of the webapplications, we connected a dropcam feed to the webapplication that would allow even remote users to see the actual change on the physical device.
An interesting challenge for this concept was the possibility of having multiple users be able to interact with it from a mobile or webapplication, without getting in the way of each other. We therefore decided to have users 'claim' or 'lock' a letter before being able to change it. This would guarantee that every user would be able to see a change take place on the device itself through the camera feed, and prevent that users would not visually get any feedback if, for example, two changes would succeed each other in very rapid fashion (because of two users changing the same letter at the same time).